diff --git a/gcc/rust/ast/rust-ast-collector.cc b/gcc/rust/ast/rust-ast-collector.cc
index 709908bd5445..3e4372e8e494 100644
--- a/gcc/rust/ast/rust-ast-collector.cc
+++ b/gcc/rust/ast/rust-ast-collector.cc
@@ -2061,8 +2061,7 @@ TokenCollector::visit (ConstantItem &item)
     }
   else
     {
-      auto id = item.get_identifier ();
-      push (Rust::Token::make_identifier (UNDEF_LOCATION, std::move (id)));
+      push (Rust::Token::make_identifier (item.get_identifier ()));
     }
   push (Rust::Token::make (COLON, UNDEF_LOCATION));
   visit (item.get_type ());
diff --git a/gcc/rust/ast/rust-ast.cc b/gcc/rust/ast/rust-ast.cc
index 5b797e8c49be..faaa11398aff 100644
--- a/gcc/rust/ast/rust-ast.cc
+++ b/gcc/rust/ast/rust-ast.cc
@@ -620,7 +620,7 @@ ConstantItem::as_string () const
 {
   std::string str = VisItem::as_string ();
 
-  str += "const " + identifier;
+  str += "const " + identifier.as_string ();
 
   // DEBUG: null pointer check
   if (type == nullptr)
diff --git a/gcc/rust/ast/rust-ast.h b/gcc/rust/ast/rust-ast.h
index 49dfcde59484..af7ac18e7a61 100644
--- a/gcc/rust/ast/rust-ast.h
+++ b/gcc/rust/ast/rust-ast.h
@@ -62,6 +62,8 @@ class Identifier
     return ident == other.ident;
   }
 
+  operator const std::string & () const { return ident; }
+
 private:
   std::string ident;
   location_t loc;
diff --git a/gcc/rust/ast/rust-item.h b/gcc/rust/ast/rust-item.h
index 2f53f8d117e4..f09154098098 100644
--- a/gcc/rust/ast/rust-item.h
+++ b/gcc/rust/ast/rust-item.h
@@ -2450,7 +2450,7 @@ class ConstantItem : public VisItem, public AssociatedItem
   // either has an identifier or "_" - maybe handle in identifier?
   // bool identifier_is_underscore;
   // if no identifier declared, identifier will be "_"
-  std::string identifier;
+  Identifier identifier;
 
   std::unique_ptr<Type> type;
   std::unique_ptr<Expr> const_expr;
@@ -2460,7 +2460,7 @@ class ConstantItem : public VisItem, public AssociatedItem
 public:
   std::string as_string () const override;
 
-  ConstantItem (std::string ident, Visibility vis, std::unique_ptr<Type> type,
+  ConstantItem (Identifier ident, Visibility vis, std::unique_ptr<Type> type,
 		std::unique_ptr<Expr> const_expr,
 		std::vector<Attribute> outer_attrs, location_t locus)
     : VisItem (std::move (vis), std::move (outer_attrs)),
@@ -2468,7 +2468,7 @@ class ConstantItem : public VisItem, public AssociatedItem
       const_expr (std::move (const_expr)), locus (locus)
   {}
 
-  ConstantItem (std::string ident, Visibility vis, std::unique_ptr<Type> type,
+  ConstantItem (Identifier ident, Visibility vis, std::unique_ptr<Type> type,
 		std::vector<Attribute> outer_attrs, location_t locus)
     : VisItem (std::move (vis), std::move (outer_attrs)),
       identifier (std::move (ident)), type (std::move (type)),
@@ -2511,7 +2511,7 @@ class ConstantItem : public VisItem, public AssociatedItem
 
   /* Returns whether constant item is an "unnamed" (wildcard underscore used
    * as identifier) constant. */
-  bool is_unnamed () const { return identifier == "_"; }
+  bool is_unnamed () const { return identifier.as_string () == "_"; }
 
   location_t get_locus () const override final { return locus; }
 
@@ -2556,7 +2556,7 @@ class ConstantItem : public VisItem, public AssociatedItem
     return type;
   }
 
-  std::string get_identifier () const { return identifier; }
+  const Identifier &get_identifier () const { return identifier; }
 
   Item::Kind get_item_kind () const override
   {
diff --git a/gcc/rust/hir/rust-ast-lower-extern.h b/gcc/rust/hir/rust-ast-lower-extern.h
index eb4474b8fe52..002e6652e11a 100644
--- a/gcc/rust/hir/rust-ast-lower-extern.h
+++ b/gcc/rust/hir/rust-ast-lower-extern.h
@@ -99,7 +99,7 @@ class ASTLoweringExternItem : public ASTLoweringBase
 	  = static_cast<AST::IdentifierPattern &> (param.get_pattern ());
 	Identifier param_name = param_kind == AST::Pattern::Kind::Identifier
 				  ? param_ident.get_ident ()
-				  : std::string ("_");
+				  : Identifier ("_", param.get_locus ());
 
 	HIR::Type *param_type = ASTLoweringType::translate (param.get_type ());
 
diff --git a/gcc/rust/lex/rust-token.cc b/gcc/rust/lex/rust-token.cc
index e1eb78f66a67..27fe8c7603bb 100644
--- a/gcc/rust/lex/rust-token.cc
+++ b/gcc/rust/lex/rust-token.cc
@@ -20,6 +20,7 @@
 #include "rust-token.h"
 #include "rust-diagnostics.h"
 #include "rust-unicode.h"
+#include "rust-ast.h"
 
 namespace Rust {
 // Hackily defined way to get token description for enum value using x-macros
@@ -234,6 +235,13 @@ escape_special_chars (const std::string &source, Context ctx)
 
 } // namespace
 
+TokenPtr
+Token::make_identifier (const Identifier &ident)
+{
+  std::string str = ident;
+  return make_identifier (ident.get_locus (), std::move (str));
+}
+
 std::string
 Token::as_string () const
 {
diff --git a/gcc/rust/lex/rust-token.h b/gcc/rust/lex/rust-token.h
index 09814c57e891..193284dbdbb1 100644
--- a/gcc/rust/lex/rust-token.h
+++ b/gcc/rust/lex/rust-token.h
@@ -24,6 +24,10 @@
 #include "rust-unicode.h"
 
 namespace Rust {
+
+// used by Rust::Token::make_identifier
+class Identifier;
+
 // "Primitive core types" in Rust - the different int and float types, as well
 // as some others
 enum PrimitiveCoreType
@@ -329,6 +333,8 @@ class Token
     return TokenPtr (new Token (IDENTIFIER, locus, std::move (str)));
   }
 
+  static TokenPtr make_identifier (const Identifier &ident);
+
   // Makes and returns a new TokenPtr of type INT_LITERAL.
   static TokenPtr make_int (location_t locus, std::string &&str,
 			    PrimitiveCoreType type_hint = CORETYPE_UNKNOWN)